- Ophelia Lovibond - Jessica Rattenbury
- Bradley James - Jack Roth
- Michael Pennington - Dr. Melville
- Neil Pearson - Dr. Stringer
- Nathaniel Parker - Philip Coleman
- Joanna Lumley - Esme Ford
- Julian Wadham - Tom Rattenbury
- Rachael Stirling - Zoë Kenneth
- Tom Riley - Philip Horton
- Richard Johnson - Augustus Mortmaigne
- Jenny Seagrove - Cecile Rattenbury
- Oliver Milburn - Charlie Newton
- Jack Gordon - James Coupland
- Guy Henry - Professor Pelham
- Michael Simkins - Manfred Canter
- Ian McNeice - Reverend King
- Haydn Gwynne - Sandra Walters
- Gerard Horan - DC Hooper
- Tom Mison - Dorian Crane
- David Ryall - Mr. Cooper
- Stella Gonet - Frances Woodville
- Hugh O'Conor - Father Jasper
- Jonathan Bailey - Titus Mortmaigne
- Trevor Byfield - Bone
- Taron Egerton - Liam Jay
- James Davies - Jarvis Patterson
- Shola Adewusi - Cleaner
- Renee Montemayor - Jacinta
- Lucy Griffiths - Madeleine Escher
- Lucy Speed - Louise Cornish
- Nina Sosanya - Lilian Hunter
- Tom Brooke - Brian Miller
- Finn Cole - Ollie Tedman
- Marty Cruikshank - Woman Interviewee
- Liz Crowther - Mrs. Leeming
- Bryan Dick - Phil Beaumont
- Daniel Sharman - Richard Scott
- Geoffrey Breton - Joe Myers
- Josephine Tewson - Hazel O'Brien
- Gabrielle Lloyd - Eileen Norman
- Eva Sayer - Anna Mallory
- Richard Lintern - Sefton Linn
- Sian Thomas - Ingrid Nielson
- Adrian Rawlins - Harry Bundrick
- Richard Dillane - Theodore Platt
- Anna Massey - Prof. Margaret Gold
- Anna Madeley - Anne Sadikov
- Emily Beecham - Nell Buckley
- Caroline O'Neill - Susan Chapman
- Philip Battley - Will McEwan
- Matthew Marsh - Henry McEwan
- Chiké Okonkwo - Jonjo Read
- Kate Miles - Nova Rose
- Bruce Mackinnon - Conan Jones
- Deborah Findlay - Lady Hugh
- Zoe Boyle - Hope Ransome
- Ben Aldridge - Daniel Rattenbury
- Camilla Arfwedson - Scarlett Mortmaigne
- Juliet Aubrey - Selina Mortmaigne
- Warren Clarke - Roger Temple
- Deborah Cornelius - Dr. Ella Ransome
- Sophie Ward - Isobel Crompton
- Robert Hardy - Sir Arnold Raeburn
- Diana Quick - Gwen Raeburn
- Annabelle Apsion - Babs Temple
- Andrew Hawley - Jez Haydock
- Bernard Lloyd - Ted Temple
- Christopher Bowen - Professor Andrew Crompton
- Zoe Telford - Freya Carlisle
- Kathryn O'Reilly - Poppy Toynton
- Juliet Stevenson - Diana Ellerby
- Hattie Morahan - Ruth Brooks
- Antonia Campbell-Hughes - Chloe Brooks
- Saskia Reeves - Alison McLennan
- Stephanie Street - Lakshmi Eyre
- Cherie Lunghi - Grace Orde
- Lucy Boynton - Zoe Suskin
- David Westhead - Leon Suskin
- Anna Chancellor - Judith Suskin
- Lorcan Cranitch - Liam Cullen
- Elize du Toit - Andrea De Ritter
- Leanne Rowe - Carly Cliff
- Oliver Johnstone - Vincent Vega
- Annabel Mullion - Thea Falconer
- James Fleet - Dr. Alex Falconer
- Nadine Lewington - Liv Nash
- Alex Jennings - Rev. Conor Hawes
- Matilda Ziegler - Helena Wright
- Richard Durden - John Gracey
- Celia Imrie - Michelle Marber
- Daisy May - Mia Wallace
- Julie Cox - Miranda Thornton
- Freddie Fox - Sebastian Dromgoole
- Roxanne McKee - Briony Keagan
- Josh O'Connor - Charlie Stephenson
- Toby Stephens - David Connelly
- Daniel Lapaine - Kit Renton
- Jo-Anne Stockham - Helen Mitchell
- Abigail Hardingham - Jessica Lake
- Georgia Taylor - Honey Addams
- Ciarán McMenamin - Nick Addams
- Lucy Cohu - Marion Hammond
- Con O'Neill - Dr. Bob Massey
- Leila Mimmack - Yasmin Randall
- Kemi-Bo Jacobs - WPC Julie Lockhart
- Kemi-Bo Jacobs - DC Lockhart
- Anna Wilson-Jones - Stanza Massey
- Harriet Madeley - Emily Robinson
- Richard Southgate - Will Pascoe
- David Soul - Paul Yelland
- David Calder - Andrew Lipton
- Pippa Bennett-Warner - Nina Clemens
- Jason Durr - DI Peterson
- Jake Curran - Adam Pettle
- Nancy Carroll - Anne Rand
- Patrick Baladi - Robert Fraser
- Rita Davies - Edna O'Brien
- Edwin Thomas - Reuben Beatty
- Catherine Steadman - Polly Beatty
- Beatie Edney - Justine Skinner
- Tuppence Middleton - Vicki Walmsley
- Neil Stuke - Professor Andrew Crane
- Dominic Mafham - Frank McLean
- Emily Joyce - Jane Grace
- Sanjeev Bhaskar - Kanan Dutta
- Lesley Vickerage - Katherine Dutta
- Simon Wilson - Dr. Matt Whitby
- Lia Williams - Emma Barnes
- Peter Davison - Peter Faulkner
- Camilla Power - Tara Faulkner
- Babou Ceesay - DC Alex Gray
- Alison Steadman - Rev. Martha Seager
- Miranda Raison - Stella Drew
- Edward Fox - Dr. Yardley
- Crystal Leaity - Rachel Cliff
- Andrew Paul - Ron Tibitt
- Kirsten Foster - PC Stapleton
- Stephen Churchett - Richard Seager
- Jane Slavin - Debbie Cliff
- Ariyon Bakare - Carl Drew
- Josh Bolt - Adam Tibitt
- Katrine De Candole - Davina Garland
- Naomi Scott - Sahira Desai
- Jaygann Ayeh - Nate
- Francesca Zoutewelle - Jess Tallison
- Aisling Bea - Hotel Receptionist
- Adam James - Ethan Croft
- Susannah Doyle - Jean Croft
- Ruth Gemmell - Robyn Strong
- Sally Bretton - Eve Rigby
- Ian Mercer - Lester Garvey
- Anna Koval - Diane Baxter
- Jamie Michie - Brian Kaye
- Alan Davies - Marcus Richards
- Timothy West - Donald Terry
- Jack Fox - Alfie Wilkinson
- Tabitha Wady - Ava Taylor
- Nicholas Farrell - Charles Milner
- Alastair Mackenzie - Sebastian Anderson
- Emma Cleasby - Jessica Neill
- Kazia Pelka - Susan Banks
- Helen Grace - Gwen Milner
- Paul Reynolds - Mr. Davies
- Tim Pigott-Smith - Jasper Hammond
- Nicholas Jones - Philip Hathaway
- Doreen Mantle - Joan
- Bobby Lockwood - Sam Langton
- Dan Reed
- Maurice Phillips
- Bille Eltringham
- Rachel Bennette
- Colin Dexter
- Alan Plater
- Chris Burt
- Damien Timmer
- Michele Buck
Daniel Lapaine hace el papel de Kit Renton.
Adrian Rawlins hace el papel de Harry Bundrick.
Richard Lintern interpreta a Sefton Linn en la serie.
Ian McNeice interpreta a Reverend King en la serie.
Warren Clarke hace el papel de Roger Temple.
Jake Curran interpreta a Adam Pettle en la serie.
Kevin Whately interpreta a Detective Inspector Robert 'Robbie' Lewis en la serie.
Laurence Fox interpreta a Detective Sergeant James Hathaway en la serie.
Clare Holman hace el papel de Dr. Laura Hobson.
Rebecca Front hace el papel de Chief Superintendent Jean Innocent.
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